The author presents a single case report of an exceptional association between fourth nerve palsy and ipsilateral Horner’s Syndrome. The case is presented alongside magnetic resonance images (MRI) which reveal a mass in the right cavernous sinus. The 54-year-old woman presented with vertical diplopia and neck pain due to torticollis of recent onset. In the primary position, positive vertical deviation of six prism dioptres was measured. She displayed mild ptosis of her right eyelid. Examination revealed anisocoria, with miosis in the right eye, increasing in the dark. Twenty minutes after apraclonidine 0.5% drops were instilled in both eyes; sympathetic denervation (Horner’s syndrome) was evident on the right with lid ptosis reversion and mild mydriasis. The rest of the ocular exam was unremarkable. On reviewing old photographs of the patient, there was no evidence of Horner’s syndrome. The patient was followed up for 19 years which revealed no variation in Horner’s syndrome or diplopia. Initial MRI revealed a mass in the cavernous sinus, consistent with a meningioma of the lateral wall. This mass was unchanged during the 19 years of follow-up. The authors conclude that the lesion in the cavernous sinus wall affected the fourth cranial nerve, whilst the presence of an ipsilateral Horner’s syndrome could be explained by the damage this lesion caused through anastomotic communication with the sympathetic plexus. They discuss that lesions within the cavernous sinus should be considered in any patients presenting with a fourth cranial nerve palsy and ipsilateral Horner’s syndrome.